Thermal barrier coatings (TBCs) applied to turbine airfoils are well known in the art for protecting parts such as blades and vanes from elevated operating temperatures within a gas turbine engine. However, TBCs are subject to degradation over their service life, and need to be inspected periodically to assess the integrity of the coating. Further, inspection of cooling ducts/openings in turbine airfoils is needed.
Other components within a gas turbine engine also need to be periodically inspected, such as vanes and blades in a compressor of the gas turbine engine for cracks or surface damage. It is also necessary to inspect the locations where the compressor vanes are coupled to a vane carrier to make sure the vanes are properly seated. Inspection of other gas turbine engine components such as combustor baskets is also required.
In the past, inspection of gas turbine engine components has been performed by partially disassembling the turbine engine and performing visual inspections on individual components. In-situ visual inspections may be performed without engine disassembly by using a borescope inserted into the turbine engine, but such procedures are labor intensive, time consuming, and require that the gas turbine engine be shut down, and the rotating parts held stationary for the inspection. Other inspections techniques have also been proposed, such as those disclosed in U.S. Pat. No. 6,992,315 and Patent Application Publication Nos. U.S. 2006/0078193 A1 and U.S. 2006/0088793 A1, the entire disclosure of each of these published patent and applications is hereby incorporated by reference herein.
An improved system for monitoring components within a gas turbine engine is desired.